import java.util.Scanner;

public class DecisionPrime {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        int i = 2;
        if (n == 1) {
            System.out.println(n + "不是素数");
        }else{
            for (; i <= Math.sqrt(n); i++) {
                if (n % i == 0) {
                    System.out.println(n + "不是素数");
                    break;
                }
            }if(i > Math.sqrt(n)){
                System.out.println(n + "是素数");
            }
        }
    }
}
